The method I've used very successfully for unknown packs is:
1) I first mount the pack in a drive that has a good absolute filter,
and has had the head load disabled, and spin it for a few hours. If the
pack shows any sign of excessive vibration, it is probably no good or
requires more serious attention. This process moves a bunch of air
through the pack, removing any loose dust.
2) I then take the pack apart, in a relatively dust-free space. Inspect
the platter for any obvious damage that may make it unusable, such as
warping, mis-centered on hub (caused by being dropped), divots in the
platter surface or signs of serious head crash(e.g., oxide gone). I
set the platter assembly on a lint-free cloth and cover with another
lint free cloth.
3) I first use a vacuum cleaner with a light brush attachment to vacuum
loose dust out of the pack case. Then I use a sink with a sprayer head
and warm soapy water to thoroughly clean the plastic parts of the disk
pack, and rinse thoroughly with clear water. I use dried compressed air
to blow out all the moisture, and then set the pack parts aside on a
lint-free cloth to dry out thoroughly, usually for 24 hours
4) I use 3M LCD monitor cleaning pads (which are lint-free by nature) to
wipe the platter surfaces to remove excess oxide and remaining dust. I
use a light pressure. Any areas that are clearly discolored get extra
treatment. I wipe in a circular (spiral) motion from the hub outward to
the edge of the platters. It's a little tedious from a handling
perspective, juggling the platter with one hand, and managing the wiping
with the other. I end up using quite a few of the wipes, as they get
dirty pretty fast.
5) I use a bright flashlight to spot any remaining dust and canned air
to dislodge any that I find. If air doesn't work, then I use more wipes
to remove any that I can see.
6) Once over with canned air to blow off any remaining dust.
7) Quickly reassemble the patter into the pack casing
8) Spin the pack again for a few hours with no head load.
9) Cross fingers, put in a "live" drive, spin it up, and hope for no bad
Based on Klemens' method, this is probably being overly cautious, but
it's worked well for me.